Treatment of patients in coma by nerve stimulation

Abstract

A method of treating a patient in coma is performed by placing an electrode in juxtaposition with a preselected cranial nerve of the patient for electrical stimulation of the nerve, applying an electrical pulse waveform to the electrode to stimulate the cranial nerve, and adjusting electrical parameters of the pulse waveform to modulate electrical activity of the nerve in an effort to rouse the patient from the coma. The patient's response to the treatment is monitored and assessed by the attending physician according to Glasgow coma scale. The preferred cranial nerve is the vagus nerve, and the stimulation is performed either for acute treatment by positioning an esophageal electrode in the patient for stimulating a region of the vagus nerve in the neck, or for longer term treatment by implanting a nerve electrode on the vagus nerve. The electrical parameters of the pulse waveform to be adjusted, by programming, include pulse frequency, pulse width, pulse current, pulse voltage, waveform on time, and waveform off time. The programming is performed to control the patient's EEG activity by said modulation of the electrical activity of the vagus nerve. Preferably, the EEG activity is desynchronized.

What is claimed is: 
     
       1. A method of treating a patient in coma, comprising the steps placing at least one electrode of an electrode array in juxtaposition with a preselected cranial nerve of the patient for electrical stimulation thereof;   applying an electrical pulse waveform to said electrode array to stimulate said cranial nerve; and   adjusting electrical parameters of said pulse waveform to modulate electrical activity of said cranial nerve in an effort to rouse the patient from the coma.   
     
     
       2. The method of claim 1, further including monitoring the response of the patient to the treatment according to Glasgow coma scale, to determine degree of conscious impairment of the patient. 
     
     
       3. The method of claim 1, wherein the step of placing said at least one electrode comprises placing said electrode array as a bipolar electrode array in juxtaposition with the patient's vagus nerve. 
     
     
       4. The method of claim 3, further including monitoring the response of the patient to the treatment according to Glasgow coma scale, to determine degree of conscious impairment of the patient. 
     
     
       5. The method of claim 1, wherein the step of placing said at least one electrode comprises positioning an electrode in the patient's throat for stimulating a region of the vagus nerve in the patient's neck. 
     
     
       6. The method of claim 1, wherein the step of placing said at least one electrode comprises implanting said electrode array as a bipolar nerve electrode array on the vagus nerve in the neck of the patient. 
     
     
       7. The method of claim 6, wherein the step of adjusting includes programming electrical parameters of said pulse waveform comprising at least some of the parameters of pulse frequency, pulse width, pulse current, pulse voltage, waveform on time, and waveform off time. 
     
     
       8. The method of claim 7, wherein the step of applying said pulse waveform to the electrode array comprises periodically applying the pulse waveform with programmed electrical parameters to the patient's vagus nerve. 
     
     
       9. The method of claim 7, wherein the step of applying said pulse waveform to the electrode array comprises continuously applying the pulse waveform with programmed electrical parameters to the patient's vagus nerve. 
     
     
       10. The method of claim 7, wherein the step of programming electrical parameters of said pulse waveform comprises programming said electrical parameters of the pulse waveform to modulate electrical activity of the patient's vagus nerve when the pulse waveform is applied to the electrode array thereon so as to exercise control over the patient's EEG activity. 
     
     
       11. The method of claim 10, wherein the step of programming electrical parameters of said pulse waveform comprises programming said electrical parameters of the pulse waveform to modulate electrical activity of the patient's vagus nerve when the pulse waveform is applied to the electrode array thereon so as to desynchronize the patient's EEG activity. 
     
     
       12. The method of claim 10, wherein the step of programming electrical parameters of said pulse waveform comprises programming said electrical parameters of the pulse waveform to modulate electrical activity of the patient's vagus nerve when the pulse waveform is applied to the electrode array thereon so as to synchronize the patient's EEG activity. 
     
     
       13. The method of claim 10, further including monitoring the patient's EEG activity to determine whether said EEG activity is synchronized or desynchronized, and wherein the step of programming electrical parameters of said pulse waveform comprises programming said electrical parameters of the pulse waveform to modulate electrical activity of the patient's vagus nerve when the pulse waveform is applied to the electrode array thereon so as to reverse the synchronicity or desynchronicity of the patient's EEG activity as determined by said monitoring. 
     
     
       14. The method of claim 13, further including monitoring the response of the patient to the treatment according to Glasgow coma scale, to determine degree of conscious impairment of the patient. 
     
     
       15. A method of therapy for a comatose patient, comprising the steps of: placing an electrode array on said patient to electrically interact with a preselected cranial nerve of the patient;   applying an electrical pulse waveform to said electrode array to stimulate said preselected cranial nerve; and   programming electrical parameters of said applied pulse waveform to modulate electrical activity of said cranial nerve in an effort to rouse the patient from the coma.   
     
     
       16. The method of claim 15, further including monitoring the response of the patient to the therapy according to Glasgow coma scale, to determine degree of conscious impairment of the patient. 
     
     
       17. The method of claim 15, wherein the step of placing said electrode array comprises placement thereof to electrically interact with the patient's vagus nerve, so that upon applying said waveform to the electrode array, the electrical interaction therebetween will stimulate the patient's vagus nerve. 
     
     
       18. The method of claim 17, wherein the step of programming electrical parameters of said pulse waveform comprises programming at least some of the parameters of pulse frequency, pulse width, pulse current, pulse voltage, waveform on time, and waveform off time of said applied pulse waveform. 
     
     
       19. The method of claim 18, wherein the step of programming electrical parameters of said pulse waveform comprises programming said electrical parameters of the pulse waveform to modulate electrical activity of the patient's vagus nerve when the pulse waveform is applied to the electrode array on the patient so as to exercise control over the patient's EEG activity.